This invention relates to the measurement of motion of vibratory equipment.
Vibration inducing mechanisms have long been employed with resiliently mounted equipment designed for such uses as screening, milling, polishing, mixing and the like. To provide a versatile mechanism capable of a plurality of vibratory motions to accomplish varying tasks, systems have been devised employing a plurality of eccentric weights which can be adjusted relative to one another and driven by a common motor. One most common such arrangement includes a motor mounted to the resiliently mounted mechanism and having the shaft of the motor support an eccentric weight on each end thereof. The weights may be varied in magnitude of imbalance and also arranged at any lead angle with respect to one another. These mechanisms produce a three-dimensional elliptical motion which can be described by three independent parameters, these parameters being two orthogonal displacements and a phase angle.
It has been found in the past that amplitude measurements can be made by direct observation of the motion of the vibrating equipment. Such direct observations have been made easier by the use of two appropriately arranged line segments such that they diverge at a given angle positioned on the vibrating machinery. When viewed during vibration of the equipment, the lines will appear to intersect and the point of their intersection determines the amplitude of vibration in the direction roughly perpendicular to the lines. However, the two independent amplitude measurements are insufficient to completely describe the three degrees of freedom of elliptical motion. The phase angle of the elliptical vibration helps determine the motion defined by the material being processed in the vibratory equipment. Such amplitude measurement devices do not indicate this phase angle.